Fox’s estrogen-infused Sandra Bullock-Melissa McCarthy comedy, “The Heat,” which estimated a strong $40 million opening, easily won the arm-wrestling match with Sony’s bro actioner “White House Down” as it sputtered with a projected $25.7 million. However, neither film was able to pin down Disney/Pixar’s family holdover “Monsters University,” which fell just 44% in its second frame for an estimated $46.2 million.

“Monsters University” reached a stellar $171 million Stateside through Sunday, with just north of $300 million worldwide, including nearly $130 million from 37 overseas territories.

Also on the animation front, Universal kick started its global rollout for “Despicable Me 2,” launching the film this weekend in six territories, which contributed to a stellar $41.5 million weekend gross and an overseas cume past $50 million. U bowed the toon last weekend in Australia. Pic bows Wednesday Stateside.

Despite the underperformance from “White House Down,” which stars Channing Tatum and Jamie Foxx, the weekend’s domestic box office was down year-over-year for only the fourth time this summer. This weekend trailed last year by roughly 10%, though overall summer totals (from May 3-June 30) still are up over 2012 by nearly the same percentage.

Helping boost weekend totals, Paramount’s big-budget risk “World War Z” continues to prove its mettle, falling just 55% in its second outing, with an estimated $29.8 million. Pic’s cumed $123.7 million domestically and $135.3 million overseas, thanks to the film’s strong $70 million-plus international gross this weekend.

Meanwhile, Warner Bros. and Legendary Pictures’ “Man of Steel” dropped only 50% in its third frame, estimating $20.8 million for a domestic cume approaching $250 million (the same as its production budget). Globally, “Man of Steel” crossed the $500 million mark this weekend.

Sony and Fox each launched their Stateside entries only in a few smaller day-and-date territories, with plans to expand the films internationally over the coming weeks.

At the specialty box office, Sony Pictures Classics’ “I’m So Excited” averaged a solid $20,546 from five debut locations. The film, which is the latest from Spanish helmer Pedro Almodovar, totaled an estimated $102,730.

‘Down’ and out at domestic B.O.?

Though CinemaScore reported an ‘A-‘ rating for the film (and Sony is reporting “excellent exit polls”), the $150 million-budgeted Sony film enters a highly competitive holiday play period, during which holdovers and new entries, including “The Lone Ranger” and “Despicable Me 2,” will crowd the market.

That said, mid-weeks (excluding the Fourth itself on Thursday) and weekend grosses should be characteristically robust.

“We love the movie, and we believe in it,” said Sony distribution head Rory Bruer. “We’re not giving up.”

Sony has had a rough summer so far, with its earlier bomb “After Earth,” which cost north of $100 million (not including marketing), grossing just $189 million worldwide and counting. Still, the studio had a solid hit with “This Is the End,” thanks to a manageable $32 million budget and nearly $75 million earned so far at the box office.

For “White House Down,” meanwhile, there’s only a faint hope that the film can gross four times its opening and reach $100 million domestic, based on the competitive B.O. landscape and past comparisons. Last year, Fox’s “Prometheus” cumed only two-and-a-half times its opening, and it also scored an ‘A-‘ CinemaScore.

Also, “Magic Mike” — another Tatum starring vehicle — bowed this same weekend last year with $39.1 million and went on to gross less than three times its domestic debut. That was with rabid word-of-mouth among women, who boosted the pic’s mid-week ticket sales and holdover frames.

Femmes raise ‘Heat’ index

Chris Aronson, Fox’s domestic distribution prexy, credited women as the driving force behind “The Heat’s” opening box office success, though the film still played slightly less skewed than “Bridesmaids” last year.

“The Heat” scored 35% of its opening from men, while “Bridesmaids” had a 33% opening male turnout. Moreover, the Fox film played better to under-25 auds (with 33%), while “Bridesmaids,” which helped make McCarthy a surprising box office powerhouse, saw 23% of its debut come from the same age group. Both films were directed by Paul Feig.

As a good indicator of decent word-of-mouth, “The Heat” saw a 6% improvement from Friday to Saturday. The film scored an overall ‘A-‘ CinemaScore.